A disposable diaper is known as an absorbent article that absorbs excretory fluid. One type of such an absorbent article is a so-called open type diaper. The opentype diaper includes an absorbent main body that is placed against a wearer's crotch where each end section of the absorbent main body in a longitudinal direction is provided with a pair of left and right side flaps that are formed to protrude in a width direction. In the use of such a diaper, the diaper is put on a wearer by pulling the diaper to the left and right in the width direction with the left and right side flaps.
Patent literatures 1 and 2 disclose a method of manufacturing such an open type diaper. In other words, there is a description that respective side flaps at the left and right in the width direction are cutout as mutually separate members and each side flap is individually joined to each of the left and right side section (each end section in the width direction) of a continuous body of absorbent main bodies that continues in a transport direction.